Effects of treatments on the properties of polyester based hemp composite

Abstract

The aim of present study is to enhance the properties of polyester based hemp composites by using different treatments. The effect of different treatments, such as alkali and benzoylation (chemical treatments), and sodium bicarbonate (ecofriendly treatment), on water absorption, and mechanical & dynamic mechanical properties of hemp/polyester composites has been studied. The composites are prepared by hand lay-up technique using constant (15 wt. %) fibres content. Water absorption properties are investigated in terms of maximum water uptake, and sorption, diffusion & permeability coefficients. Dynamic mechanical properties, such as storage modulus (<i>E</i>'), glass transition temperature (<i>T_g</i>) & damping (<i>Tanδ</i>), and mechanical properties such as tensile strength & modulus, flexural strength & modulus and impact strength are also investigated. The results suggest a significant effect of chemical treatment in terms of increase in mechanical and dynamic mechanical properties, and decrease in water absorption properties. The benzoylation treatment shows the better impact among all three chemical treatments.